Sealed joint



Dec. 15, 1936.

D. D. CRANDELL SEALED JOINT Filed Feb. 28, 1sss INVENTOR Dean D. Crandell,

' A O'R-NEYS Patented Dec. 15, 1$36 PATENT OFFICE SEALED JOINT Dean D. Craudell, Buifalo, N.'Y., assignor to National Gypsum Company, Bufialo, N. Y.

Application February 28, 1936, Serial No. 66,284

2 Claims.

This" invention relates to an improvement in finishing wall and ceilings .to produce a smooth and continuous surface, and particularly to a system for producing acovered joint between 5 adjacent panels forming a wall or ceiling that can be covered with a decorative coating of paint or paper without interposition of a cementitious coating such as'lime or plaster.

Attempts have been made heretofore to construct walls or ceilings of panels without using a plastering finish prior to the final-decorative coat. Thus it has been proposed to pack a cementitious filling material within the joint or open seam between the edges of adjacent wall a board panels, but this does not yield an unmarked, smooth and continuous surface since there is contraction and expansion of the wall or ceiling with consequent opening up at the joint, with consequent rupture'of the decorative 9 film. The use of fabric tapes as a joint reinforcement has been found unsatisfactory since where a filler is used back of the tape this often cracks and falls or' pulls away and, where there is no filler, breathing occurs with deposition of dust with the formation of unsightly marks following thejoint. Reinforcements of wire mesh or perforated tape have been used to some extent but the mesh is generally too thick for use where a paper or paint finish is to be applied with a previous plaster coat. Where cloth fabrics have been used to tape wall board joints, it has been found that the cloth stretches in expansion and bulges upon return of the panels to the original position. Thin metal tapes perforated to form a mechanical key have been suggested, but must be used with a joint filler to have the proper ,binding or keying action and upon compression the filler is prone to crack and the perforated tape loosen.

40 In some cases unsightly joints are formed by the protrusion of the joint filler mechanical key through the perforations of the tape; if there is no protrusion the mechanical key may work away from the tape.

An object of the present invention is the provision of a smooth continuous surface covering the joint which will take a paint or paper decorative coating without the necessity of intermediate plastering, and a joint which possesses a strength in excess of that posessed by the panels themselves so that rupture at the joint is eliminated. 1

Another object of the invention is the formation of a joint that will not breathe and show a deposit of soot and dust along the line of the joint with consequent discoloration of the decoratiye surface.

The accompanying drawing is a perspective view of the improved joint system.

In the application of the paper or cloth fabric joints used heretofore, the paper or fabric tape was glued to the edges of adjacent wall board either with or without a joint filler. Where joint filler was used, this filler is prone to crack and fall away and breathing occurs through the paper or fabric tape at a rate difierent from the rest of the structure with discoloration. A further disadvantage of this fabric or paper tape joint system is the relative weakness thereof and the ease with which it can be ruptured. As contrasted to the prior fabric tape joint capable of withstanding only about 20 pounds, the joint of the present invention will withstand 60-65 pounds or better. That is to say, the joint is stronger than the wall board itself.

The unusual strength or reinforcement of the 'joint is obtained by the use of a cloth fabric tape of balloon cloth, a fabric cloth wherein the individual strands are made of tightly twisted fibers and strands which are closely woven, as contrasted with the relative open weave of canvas tapes heretofore used.

' Where heretofore cloth fabric tapes have been glued at their edges to adjacent wall board, in the present improved joint system the whole tape is saturated throughout with a strong, tough and elastic waterproof glue, such as casein glue, and this saturated tape applied to the edges of adjacent wall boards. As this drys a drum effect is obtained, since thereis a marked shrinking of the tape and glue which tightens up the joint. With good waterproof glues, such as the casein glue mentioned, good elasticity is present in the glue so that the adjacent panels may move toward one another without bulging of the tape, and may move away from one another without rupture at the joint.

To produce the finish desired and to eliminate any suggestion of tape edge, a thin coating of casein cement is applied over the glue saturated tape and the whole sanded down. In the drawing wallboards ID are shown attached to a supporting member or stud H by means of nails l2. A joint 13 is thus formed between the adjacent wall boards andover this is placed tape l4 saturated in glue IS. The finish of the joint system is plastic casein cement l6 sanded to form tapered edges IT.

The bonding carrier of the finish cement I6 should be compatible with glue l5 so that there is fusion between the bonding element upon the tape and that in the finish, in order to get uniform elasticity throughout these elements. V

The finished joint does not show a relative rate of breathing between the joint and the rest of j the structuresince the glue is substantially impermeable to air and moisture, and the joint sysmember to form a wall board joint, a tape of finely woven fabric placed over said joint, said tape being attached to the edges of adjacent panels by means of an elastic glue substantially impermesaid tape throughout and a plastic cement finish over said tape.

2. -In a wall construction a supporting member, panels having edges attached to said supporting member to form a wall board joint, a tape of finely 1 woven fabric placed over said joint, said tape being attached to the edges of adjacent panels by means of an elastic glue substantially impermeable to air and moisture, said glue permeating said tape throughout and a plastic filler with a ,1 bonding carrier of the same composition as the glue of said tape covering said tape.

' DEAN D. CRANDELL.

.able to air and moisture, said glue permeating 5 

